This invention relates to intraocular lenses (IOLs) and more particularly to cartridges use to inject IOLs into an eye.
The human eye in its simplest terms functions to provide vision by transmitting and refracting light through a clear outer portion called the cornea, and further focusing the image by way of the lens onto the retina at the back of the eye. The quality of the focused image depends on many factors including the size, shape and length of the eye, and the shape and transparency of the cornea and lens.
When trauma, age or disease cause the lens to become less transparent, vision deteriorates because of the diminished light which can be transmitted to the retina. This deficiency in the lens of the eye is medically known as a cataract. The treatment for this condition is surgical removal of the lens and implantation of an artificial lens or IOL.
While early IOLs were made from hard plastic, such as polymethylmethacrylate (PMMA), soft, foldable IOLs made from silicone, soft acrylics and hydrogels have become increasingly popular because of the ability to fold or roll these soft lenses and insert them through a smaller incision. Several methods of rolling or folding the lenses are used. One popular method is an injector cartridge that folds the lenses and provides a relatively small diameter lumen through which the lens may be pushed into the eye, usually by a soft tip plunger. The most commonly used injector cartridge design is illustrated in U.S. Pat. No. 4,681,102 (Bartell), and includes a split, longitudinally hinged cartridge. Similar designs are illustrated in U.S. Pat. Nos. 5,494,484 and 5,499,987 (Feingold) and U.S. Pat. Nos. 5,616,148 and 5,620,450 (Eagles, et al.), the entire contents of which are incorporated herein by reference. In an attempt to avoid the claims of U.S. Pat. No. 4,681,102, several solid cartridges have been investigated, see for example U.S. Pat. No. 5,275,604 (Rheinish, et al.), U.S. Pat. No. 5,653,715 (Reich, et al.) and U.S. Pat. No. 5,947,876 (Van Noy, et al.), the entire contents of which are incorporated herein by reference.
Viscoelastic lens materials, such as soft acrylics, are temperature sensitive, and roll or fold more easily at higher temperature. None of the prior art cartridges contain a feature that allows for the heating of the cartridge so as to warm the lens during insertion.
Accordingly a need continues to exist for a cartridge that allows for the heating of the cartridge so as to warm the lens during insertion.
The present invention improves upon prior art lens injector cartridges by providing a cartridge having a heat retention additive for helping the cartridge retain heat after the cartridge is warmed. Such additives can include any biocompatible material having high heat retention, for example, powdered gold.
It is accordingly an object of the present invention to provide a lens injector cartridge that folds more easily a lens made from a soft acrylic.
It is a further object of the present invention to provide a lens injector cartridge that gently folds a soft acrylic lens.
Other objectives, features and advantages of the present invention will become apparent with reference to the drawings, and the following description of the drawings and claims.